If you’ve been looking at examples of terminal commands, you will most likely have seen that there is a dollar ($) sign in front of the actual text. The dollar sign means that you are doing the command as a normal user. The pound (#) sign means that you are doing it as the root user. If you start a terminal as a normal user, you will actually see the dollar sign and the vice versa with the pound sign.
In the following example, emacs will be started as root.
$ sudo emacs
# emacs